JPS58158856A - Nonaqueous electrolytic battery - Google Patents

Abstract

PURPOSE:To improve the storage performance and leakage-proof performance of a battery with hardly making a structural change by draw-forming a stainless steel sheet, and applying annealing treatment after it is molded, so as to form a battery case. CONSTITUTION:A nonaqueous electrolytic battery is mainly composed of a stainless steel battery case 1 whose top is opened, positive electrode terminal 3 that extracts the output of a generating element 2 enclosed in the case and capable of generating operation, and a gasket 4. The battery case 1 is molded in a cylindrical shape by deep-drawing a stainless steel sheet such as SUS304 and is annealed under the condition at a temperature 1,060 to 1,070 deg.C and a pressure of 4X10<-6>mm.Hg for 30min and is cooled in the inert gas atmosphere in a comparatively short time. As a result of this treatment, the residual stress caused by the drawing process is almost removed. The storage performance and leakage-proof performance are exceedingly improved and the crack and corrosion caused by residual stress are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nonaqueous electrolyte battery, in particular, a nonaqueous electrolyte battery that uses light metals such as tutium, sodium, and potassium as a negative electrode active material, and a nonaqueous electrolyte composed of an organic solvent or the like as an electrolyte. Regarding non-aqueous electrolyte batteries.

This type of nonaqueous electrolyte battery contains lithium, sodium, potassium, calcium, and more! When light metals such as danesium and aluminum are used as negative electrode active materials,
It is characterized by the use of an organic electrolyte in which an alkali metal salt is dissolved in order to impart ionic conductivity to a non-aqueous organic solvent as an electrolyte, resulting in high energy density.

In recent years, it has been attracting attention as a small, high-performance battery because it has theoretically been proposed that it has a wide operating temperature range and long-term storage stability.

For example, when using alkali metals such as lithium, sodium, and potassium as negative electrode active materials, it is known that these metals are among the most negative substances, so it is difficult to obtain high electrical energy. Although it is easy to imagine that these metals are extremely chemically active and react violently with water to generate hydrogen, it is impossible to use ordinary aqueous electrolytes. Therefore, as a non-aqueous electrolyte, a mixture of pyrene and
Organic electrolytes in which alkali metal salts are dissolved have become widely used in order to impart ionic conductivity to non-aqueous organic solvents such as nate (PC), i-butyrolactone (BL), or dimethylformamide (DMF).
The practical application of non-aqueous electrolyte batteries is being promoted.

In known non-aqueous electrolyte batteries, manganese dioxide (MnO) or silver (Mt) are often used as positive electrode active materials, and are made from porous insulators with high ion permeability and moderate mechanical strength. The above-mentioned negative electrode active material, positive electrode active material (negative electrode, positive electrode, and non-aqueous electrolyte) are used as power generation elements through a separator made of black-plated metal plates such as iron, stainless steel, or aluminum. It was assembled into a sealed battery case and sealed to form a non-aqueous electrolyte battery.

In this known non-aqueous electrolyte battery, stainless steel plates are generally used as the battery case, but this is because stainless steel is chemically relatively stable.
This is due to the fact that a chemical reaction occurs with the electrolyte's power generation element (from Qz. However, even this stainless steel is not unconditionally safe and has sufficient performance, and the electrolyte may form during long-term storage. This caused a gradual reaction with the electrolyte, resulting in deterioration of discharge performance or leakage during storage.First, the chemical reaction occurs not only with the electrolyte, but also with the positive and negative active materials that make up the other power generation elements. The deterioration of the discharge performance is due to the fact that the inner surface of the battery nurse is chemically eroded due to a chemical reaction with the power generating element. It is thought that this is caused by impurities generated during battery life, which increases the internal resistance], and leakage is often caused by corrosion of the barb at the opening end of the battery case. This can be prevented by preventing erosion and corrosion of the battery case. However, it is generally known that residual stress during molding can cause cracks and corrosion in stainless steel used as battery nurses, especially in cases such as cylindrical batteries. 〉Since deep examination is performed, the large residual stress in this case is a problem. Furthermore, it is thought that sufficient care must be taken in storage to prevent stress corrosion of stainless steel in organic solvents during long-term storage.

The present invention has been made in view of these points, and its purpose is to provide a non-aqueous electrolyte battery using a battery case made of a stainless steel plate without making any structural changes. To provide a non-aqueous electrolyte battery that improves the storage performance and leakage resistance of the battery, the present invention is characterized by forming a battery case by processing and forming a cystine-less steel plate, and then subjecting it to an annealing treatment. There is.

Hereinafter, the present invention will be explained in detail based on an example of implementation and with reference to the drawings.

In the figure, the nonaqueous electrolyte battery mainly consists of a stainless steel battery case 1 with an open top, a positive terminal 3 and a gasket 4 for taking out the output of a power generation element 2 located inside the case and having a power generation function. has been done. Power generation element 2
is formed in a spiral shape by overlapping a belt-shaped positive electrode 6 and a negative electrode 7 on both sides of a belt-shaped separator 6 in the center,
It is housed in a battery case 1 together with an insulating plate 8, and is further injected with a non-aqueous electrolyte 9 and sealed with the positive electrode terminal s$1 and a gasket 4. The positive electrode terminal 3 is connected to the positive electrode l1i6 by a positive electrode lead wire 10, and the battery nurse l is connected to the negative electrode 7 by a negative electrode lead wire 11, respectively.

The battery case 1 is made by deep drawing an 8U8304 stainless steel plate and forming it into a cylindrical shape.
3 under the conditions of 70℃, pressure 4X10 1111Hf
Annealing treatment was performed for 0 minutes, and cooling was performed in an inert gas atmosphere within a relatively short period of time. By this treatment, the residual stress caused by the drawing process was almost eliminated. In the case of the 8US304 stainless steel plate of this example, after the annealing treatment, the hardness is 150-155 with softer edges than before the treatment. In this annealing treatment process, if the heating temperature is higher than 1,300° C., the structure will become too large due to re-solidification and the strength will decrease, so care must be taken in temperature conditions.

The positive electrode 6 is made by mixing manganese dioxide with carbon powder, which is a conductive agent, and is pressure-formed into a band shape using a binder.The negative electrode 7 is a lithium metal ribbon that is crimped onto a nickel grid using a metal current collector. Like the positive electrode 6, it is formed into a band shape, and the positive electrode 6 and the negative electrode 7 are stacked on both sides of a separator 5 made of polypropylene nonwoven fabric, respectively, and wound in a spiral shape.

The nonaqueous electrolyte contains lithium chlorate (LiC) as a solute in a mixed solvent of propylene carbonate (PC) and dimethoxyethane (DME) to provide ionic conductivity.
A lower insulating plate 8. Positive electrode with spiral structure 6. Separator 5. After inserting the negative electrode 7, the non-aqueous electrolyte 9 is injected and sealed as described above.

Next, the results of a leakage test of a lithium battery using a battery case subjected to an annealing treatment and a lithium battery using a battery case not subjected to an annealing treatment are shown in the table. This table shows the materials 808304, 808305, 5U
S430 and 8U84340) In a cylindrical lithium battery formed by deep drawing press forming of a stainless steel plate, the electrolyte is a mixed solvent of propylene carbonate (PC) and dimethoxyethane (DME) and lithium chlorate (Li).
Leakage state when 100 specimens each having the same power generation element as in the above example in which carbon (Cton) was dissolved as a solute were left in an atmosphere of 60°C and 90% relative humidity for 3 to 12 months. It is a hanging.

Table According to this table, the material of the battery case is 8US304,
In all cases of 8U8305, 8US430 and 8U8434, it is clearly shown that those subjected to annealing treatment have extremely high leakage resistance performance compared to those not subjected to annealing treatment.

As described above, according to the present invention, in which the case of a non-aqueous electrolyte battery is molded from a stainless steel plate and then subjected to an annealing treatment to remove residual stress, the case of the non-aqueous electrolyte battery can be used without causing the conventional battery structure or Sa. In addition to significantly improving the storage performance and leakage resistance of batteries in general, there is no need to worry about cracking or corrosion caused by residual stress, so they can be used with peace of mind, making this type of high-performance battery available to the general public. You can contribute to budding. Furthermore, since residual stress during molding is removed extremely effectively, it is particularly effective for cylindrical non-aqueous electrolyte batteries that undergo deep drawing.

[Brief explanation of the drawing]

The figure is -I! 1 is a longitudinal cross-sectional view showing the structure of a cylindrical non-aqueous electrolyte battery used in KK. 1-Battery nurse 2-Power generation element 3-Positive electrode terminal 4-Gasket 5-Seven pallet 6-Positive electrode 7-Negative electrode 8-Insulating plate 9-Non-aqueous electrolyte l〇-Positive electrode lead wire 11-Negative electrode lead wire Patent applicant Fuji Denki Kagaku Kinsha Patent Attorney - Kensuke Iro

Claims (1)

[Claims] 1. A stainless steel plate is molded into a non-aqueous electrolyte battery having a stainless steel battery case that houses a power generating element and also serves as an electrode terminal, followed by annealing treatment. A non-aqueous electrolyte battery characterized in that a battery case is formed by applying λ The battery case is 8U8304, 5aasos,
5va4s. 2. The non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte battery is formed from a stainless steel plate made of any one of the following materials. 3. The non-aqueous electrolyte battery according to claims 1 and 2, wherein the annealing temperature in the annealing treatment of the drawn stainless steel plate is in the range of 800 to 1200°C. 4. The non-aqueous electrolyte of the non-aqueous electrolyte battery is propylene car (PC) and dimethane (]) Ml).
Lithium bifolate (LictD
, ) is formed by dissolving the @l! Item 111, Item XJ and the non-aqueous electrolyte battery described in Item 1.